When a material is made, you typically cannot change whether that material is hard or soft. But a group of University of Michigan researchers have developed a new way to design a “metamaterial” that allows the material to switch between being hard and soft without damaging or altering the material itself.

Metamaterials are man-made materials that get their properties—in this case, whether a material is hard or soft—from the way the material is constructed rather than the material that constructs it. This allows researchers to manipulate a metamaterial’s structure in order to make the material exhibit a certain property.

In the group’s study, published in the journal Nature Communications, the U-M researchers discovered a way to compose a metamaterial that can be easily manipulated to increase the stiffness of its surface by orders of magnitude—the difference between rubber and steel.

Since these properties are “topologically protected,” meaning that the material’s properties come from its total structure, they’re easily maintained even as the material shifts repeatedly between its hard and soft states.